Optical reader with combined housing and light pipe

ABSTRACT

An optical reader includes a housing which may environmentally protect the optical path between a light source and a sensor array to reduce dust and debris interfering with transmission of light. The housing may further provide for alignment of the light path by positioning a focusing axis in alignment with the optical sensor array. The housing further acts as a light pipe to reflect transmitted light from a light source toward a focusing axis where the light may be reflected off of a document containing coded information back through the chamber defined by the housing to an optical sensor array. Point of sale devices incorporating an optical reader are also provided.

This application is a continuation of application Ser. No. 09/237,143,filed Jan. 25, 1999, now U.S. Pat. No. 6,247,645.

FIELD OF THE INVENTION

The present invention relates to an optical reader in general and inparticular to optical character readers for use with point of salesystems.

BACKGROUND OF THE INVENTION

Face to face retail sales transactions take place at the point of saleor what is commonly referred to as the checkout line or counter. It isat this location that the customer pays for the goods purchased,typically by either cash, check, charge or debit card.

To effectuate the sale, many retailers presently use electronic devicesto facilitate and provide a record of transactions. Such a point of salesystem may include a scanner for reading coded product price, a terminalfor manual entry of transaction information and storage of currency, anda printer which may be used to produce a documentary record or journalfor the business and a printed receipt for the customer. Checkprocessing devices are also available to facilitate the transaction whena check is used for payment. Such check processing devices may include aMagnetic Ink Character Recognition (“MICR”) reader for reading codedaccount information printed with magnetic ink which is commonly found onthe front of checks. Optical character readers may also be provided forreading information encoded on a check.

As part of the check out procedure, the sales price of each itempurchased is entered into the point of sale terminal. When paying bycheck, the customer then provides a check for the amount due to thecashier. The cashier inserts the check into the check processing devicewhich reads the coded information such as MICR information, for furtherprocessing such as confirming sufficient fund availability or checkingthe information against a bad account list. A receipt is then providedfrom the printer to the customer.

An example of an optical reader apparatus which may be used for readingdata from a check is U.S. Pat. No. 5,345,090. This reader apparatusilluminates the document with two light sources oriented adjacent a datawindow which is aligned along an optical axis which includes a mirrorand aperature positioned to receive reflected light from the document.

It is also known to use optical fiber elements as light piping to allowthe light source to be displaced from the document to be illuminated asdescribed, for example, in U.S. Pat. No. 3,584,779. U.S. Pat. No.3,726,998 discusses an alternate approach to light piping using a flatplate light pipe rather than optical fiber elements. On the receive endfor reflected light, U.S. Pat. No. 4,495,412 describes the use of anoptical waveguide circuit in a glass substrate to route light from ascanned line to a transducer where the length of the scanned lineexceeds that of the transducer.

These known approaches to optical readers have limitations, particularlyin the relatively compact and dirty environment of point of salesystems. Point of sale systems are typically located at the checkoutcounter where space is limited. Accordingly, printer and readercomponents are often packaged together to provide both a reducedfootprint and reduced document handling requirements for a user. In suchan environment, an optical reader preferably would provide foralignment, light routing and protection from environmental dirt anddebris in a compact package. Another limitation is the cost of knownoptical readers which is, typically, higher than desired as a largenumber of point of sale devices, such as printers, are often used,making it desirable to provide a low cost reader for MICR characters.

SUMMARY OF THE INVENTION

In light of the above discussion, it is an object of the presentinvention to provide an optical reader which may be mounted in a pointof sale device.

It is a further object of the present invention to provide an opticalreader which may provide light routing and environmental protection.

It is another object of the present invention to provide an opticalreader which may be produced at a reduced cost.

These and other objects are provided according to the present inventionby an optical reader in which a housing is provided which mayenvironmentally protect the optical path between light source and asensor array to reduce dust and debris interfering with transmission oflight. The housing may further provide for alignment of the light pathby positioning a focusing axis in alignment with the optical sensorarray. The housing further acts as a light pipe to reflect transmittedlight from a light source toward a focusing axis where the light may bereflected off of a document containing coded information back throughthe chamber defined by the housing to an optical sensor array. Both thesensor and illumination capabilities of the optical reader of thepresent invention are thereby provided in a low-cost package having asmall foot print and suitable for use in point of sale devices such aspoint of sale printer devices. The optical reader may be provided in acompact form which requires no critical optical tolerances and allowsthe use of standard circuit card assembly methods in fabrication of theoptical reader.

In one embodiment of an optical reader of the present invention, anoptical reader is provided which includes a base member with an opticalsensor array connected to the base member. A housing is positioned overthe optical sensor array and a light source is positioned in a chamberdefined by the housing. The housing includes a reflecting surfaceportion positioned to receive light from the light source and direct thereceived light through the chamber towards a focusing axis at a firstend of the housing. The housing may be connected to the base member toprovide an enclosure protecting the optical sensor array and the lightsource from debris. Furthermore, the housing may be connected to thebase member so as to position the focusing axis in alignment with theoptical sensor array.

In a further embodiment of the optical reader of the present inventionthe housing includes a first portion extending up from the base member.The reflecting surface portion extends from an end of the first portionopposite the base member towards the focusing axis at an angle selectedto receive light from the light source and direct the received lightthrough the chamber towards the focusing axis. The reflecting surfaceportion of the housing may include an optically transmissive inner layerand a reflective cladding outer layer on a surface of the opticallytransmissive layer opposite the chamber.

In another embodiment of the optical reader of the present invention alight pipe is positioned in the chamber having a first end adjacent theoptical sensor array and a second end adjacent the focusing axis so asto direct light reflected from a document positioned at the focusingaxis to the optical sensor array. A view window is provided connected tothe housing and positioned along the focusing axis. The base member maybe provided as a circuit board and the light source and the opticalsensor array may be electrically connected to the circuit board.

In another embodiment of the optical reader of the present invention, asecond light source is provided positioned in the chamber and mounted onthe circuit board and electrically connected to the circuit board. Thehousing includes a second portion extending up from the base member anda second reflecting surface portion extends from an end of the secondportion opposite the base member towards the focusing axis at an angleselected to receive light from the second light source and direct thereceived light from the second light source through the chamber towardsthe focusing axis.

In a further aspect of the present invention, a point of sale device isprovided including a housing and a document driver mounted in thehousing to move a document inserted into the point of sale device alonga document travel path. A magnetic reader is mounted in the housing andpositioned along the document travel path to read MICR coded informationfrom the document. An optical reader, such as those described above, isalso mounted in the housing and positioned along the document travelpath to read the MICR coded information from the document. The opticalreader is mounted to position the focusing axis so that a portion of thedocument containing the MICR coded information passes through thefocusing axis when the document is moved along the document travel path.The ability to redundantly read MICR coded information both magneticallyand optically to improve performance in a point of sale environment isthereby provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view illustrating an embodiment of theoptical reader of the present invention;

FIG. 2 is a cross-sectional view of the optical reader shown in FIG. 1;

FIG. 3 is a perspective view illustrating an embodiment of the opticalreader of the present invention positioned in a point of sale printerdevice;

and

FIG. 4 is a flow chart illustrating operations for check processingusing an embodiment of a point of sale printer device according to thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The optical reader of the present invention will now be described morefully hereinafter with reference to the accompanying drawings, in whichembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art.

Referring now to FIGS. 1 and 2, an embodiment of an optical readeraccording to the present invention is illustrated. The optical reader 10includes a housing 12 connected to a base member 14. In the illustratedembodiment, the base member 14 is provided as a circuit board and anoptical sensor array 16 is mounted on the circuit board 14. The opticalsensor array 16 is a linear sensor array, such as the 102 by 1 linearsensor array available from Texas Instruments, Inc., and provides analogoptical read data corresponding to the light incident upon the elementsof the array.

Housing 12 is positioned over the optical sensor array 16 and isconnected to the base member 14 to provide an enclosure protecting theoptical sensor array 16 and light sources 18, 18′, 20, 20′ from debris.By positioning optical sensor array 16 and light sources 18, 18′, 20,20′ in the chamber defined by housing 12 connected to base member 14,optical reader performance may be improved by reducing particulate dustand debris matter from obscuring the optical path for light emitted fromlight sources 18, 18′, 20, and 20′ and reflected off of a documentpositioned at a focusing axis 22 on a first end of housing 12 and backto optical sensor array 16. Thus, particulate dust and debris matter maybe prevented from reducing the performance of the optical sensor arrayby scattering the light before it can be reflected and received. Thechamber defined by housing 12 connected to base member 14 may be hollow,as illustrated in the Figures. Alternatively, the housing may be moldedwith optically transmissive material throughout the chamber with spacesprovided for the various components contained within the chamber.

In addition to providing a protective enclosure, the housing 12 isconnected to the base member 14 so as to position the focusing axis 22in alignment with the optical sensor array 16.

The embodiment illustrated in FIGS. 1 and 2 further includes a lightpipe 24 positioned in the chamber defined by the housing 12 and the basemember 14. In the illustrated embodiment, the light pipe 24 is a SELFOC(available from Nippon Sheet Glass Company Ltd.) lens array. The lightpipe 24 has a first end 26 adjacent the optical sensor array 16 and thesecond end 28 adjacent the focusing axis 22. Light pipe 24 focuses theimage from a document positioned at the focusing axis 22 to the opticalsensor array 16.

The electrical connections for the components in the illustratedembodiment of FIGS. 1 and 2 are provided by circuit board 14. The lightsources 18, 18′, 20, 20′, which may be light emitting diodes (LEDs),which provide the source of light, as well as the optical sensor array16, are each connected electrically to the circuit board 14 which, inturn, may include an attached electrical cable 30. Electrical cable 30provides input connections for providing a power source to the opticalsensor 10 and further for transmitting the optical read data from theoptical sensor array 16 to a separate processing device which processesthe optical information contained in the optical read data andidentifies the associated characters printed on the document passingthrough the focusing axis 22.

In addition to providing a protective enclosure, the housing 12 acts asa light pipe to direct light received from light sources 18, 18′, 20,20′ through the chamber formed by the housing 12 and the base member 14towards the focusing axis 22. The light is directed by use of areflecting surface portion 42, 52 of housing 12 as will now be furtherdescribed for the illustrated embodiment.

As is best seen in the cross-sectional view of FIG. 2, the housing 12includes a first portion 40 extending up from the base member 14. Thehousing structure further includes a reflecting surface portion 42.

The first portion 40 of the housing 12 extends up from the base member14 and the reflecting surface portion 42, in turn, extends from an endof the first portion 40 opposite the base member 14 towards the focusingaxis 22. The angle of the reflecting surface portion 42 is selected toenable the housing 12 to act as a light pipe directing light emitted bylight sources 18, 18′ towards the focusing axis 22. The angle is,therefore, selected to receive light from light sources 18, 18′ anddirect the received light through the chamber formed by the housing 12and the base member 14 toward the focusing axis 22.

In the illustrated embodiment, the reflective characteristics of thereflecting surface portion 42 are provided by a multi-layer structure. Areflective cladding outer layer is provided on the housing 12, at leastin the region of reflecting surface portion 42. The reflective claddingouter layer is preferably deposited or otherwise placed on an outersurface of an inner optically transmissive layer which defines a wall ofthe chamber formed by the housing 12 and the base member 14.

While the reflecting light pipe characteristics of the housing 12 havebeen described above with reference to only one side of thesubstantially symmetrical structure of the housing 12, receiving lightfrom upper light sources 18, 18′, as is illustrated in FIGS. 1 and 2, asecond set of light sources 20, 20′ may be provided on the opposite sideof the chamber formed by the housing 12 and the base member 14. As wasdescribed previously for the first pair of light sources 18, 18′, thehousing 12 provides a light pipe for directing light from light sources20, 20′ towards the focusing axis 22. A first housing portion 50 extendsup from the base member 14 and a second reflecting surface portion 52extends therefrom towards the focusing axis 22 at an angle selected toreceive light from the second pair of light sources 20, 20′ and directthe received light through the chamber formed by the housing 12 and thebase member 14 towards the focusing axis 22.

The second reflecting surface portion 52 preferably has a two-layerstructure as was described with reference to the first reflectingsurface 42 including an outer layer of a reflecting cladding material 54and an inner layer of an optically transmissive material 56. The innerlayer material, which may be molded to form the housing 12, ispreferably a plastic with good optical transmission properties such asacrylic or optical grade polycarbonate.

The housing 12 may include additional features as illustrated in FIGS. 1and 2. In the embodiment shown in the FIGS. 1 and 2, a mounting tab 60is positioned on one end of the housing 12 and provides a means forconnecting the housing 12 to the base member 14. The housing 12 may beconnected to the base member 14 by a self tapping screw 62 which isinserted into a channel 64 of the mounting tab 60.

Furthermore, the end of the housing 12 defining the focusing axis 22 mayinclude an optically transmissive view window 66 which allows lightreflected from reflecting surfaces 42, 52 to pass out of the chamberdefined by the housing 12 and the base member 14 to strike a documentcontaining coded information passing through the focusing axis 22. Lightis then reflected from the document back through the view window 66 tobe directed by the light pipe 24 to the optical sensor array 16.

It is to be understood, however, that the housing 12 may instead beprovided with an open portion rather than a view window 66 providing forpassage of light to and from a document to be read. It is further to beunderstood that, while the light directing characteristics of thepresent invention have been generally described herein with reference toa focusing axis 22, the light may be only generally directed towards thefocusing axis 22 as the document to be illuminated will define afocusing plane along the focusing axis 22 having a finite width. Thefocusing plane width tangent to the focusing axis 22 is preferablyselected to optimize the amount of light from light sources 18, 18′, 20,20′ which is reflected back to the optical sensor 16 by a documentpassing through the focusing axis 22 to increase the likelihood ofsuccessfully reading information from the document.

The present invention may also be provided as a point of sale devicesuch as the point of sale printer device which is illustrated in FIG. 3.As shown in the embodiment of FIG. 3, the point of sale printer device100 includes a housing 102 which contains the various components of thepoint of sale printer device 100. The point of sale printer device 100further includes a document driver mounted in the housing 102 to move adocument inserted into the point of sale printer device 100 along adocument travel path illustrated by axis 104.

An optical reader 10 is mounted in the housing 102 and positioned alongthe document travel path 104 to read coded information from a documentpassed through the point of sale printer 100. More particularly, thepoint of sale printer device 100 illustrated in FIG. 3 is suited for usein check processing and the optical reader 10 is mounted in the housing102 to read the MICR coded information from the document. The opticalreader 10 is mounted in the housing 102 to position the focusing axis 22so that a portion of the document passing along document path 104containing the MICR coded information passes through the focusing axis22 when the document is moved along the document travel path 104. Amagnetic reader may also be mounted in the housing 102 and positionedalong the document travel path 104 to read coded information from adocument. By providing both a magnetic reader and an optical readeraccording to the present invention, the MICR coded information typicallyprovided on checks may be read using both sensors to provide forimproved reliability of character recognition for processing point ofsale transactions.

Referring again to FIG. 3, various aspects of the point of sale printerdevice 100 will now be further described. Such a point of sale printerdevice 100 is used in facilitating sales transactions at locations suchas a check out counter where a customer makes payment for merchandise.As shown in FIG. 3, a print head 200 as well as optical reader 10 arecontained within housing 102. Housing 102 further includes a documentinsertion region 202. Documents inserted into insertion region 202 aremoved, using known document handling mechanisms which will not bedescribed further herein, to allow documents inserted into the printerto be moved along document travel path 104 (represented figuratively bya directional arrow) past print head 200 and optical reader 10. Opticalreader 10 is mounted at a first position in document travel path 104.Print head 200, as illustrated, is laterally offset from optical reader10.

As shown in FIG. 3, housing 102 includes additional document insertionregion 204 particularly adapted for use with paper rolls such as thoseused for customer receipts or journal records. Document insertion region202 is adapted to sheet feed documents such as forms or checks andincludes alignment edge 206 for positioning documents fed throughdocument insertion region 202 laterally with respect to document travelpath 104. Regardless of whether documents are inserted in region 202 or204, the documents are fed along document travel path 104 past printhead 200. Documents inserted in document insertion region 202 andaligned with respect to alignment edge 206 are fed along document travelpath 104 past optical reader 10.

Print head 200 is mounted on print head carrier 208 which is movablymounted on a transport guide mechanism 210 allowing movement of printhead 200 across a document for printing. Print head 200 is locatedadjacent platen 212 and spaced from platen 212 a sufficient distance toallow documents inserted into the printer to pass between print head 200and platen 212 along document travel path 104. It is to be understoodthat platen 212 may be a rigid member serving to locate the document tobe printed by print head 200 and to serve as a strike surface for a dotmatrix printer but it is known that platen 212 may provide for locationof the document for printing in different manners for different types ofprint heads such as may be found in a laser printer.

Print head 200 may first be used to generate customer receipts and ajournal record of the items sold on paper fed either through documentinsertion region 202 or on paper fed from a spool in insertion regions204. Payment is then made by the customer for the costs of thetransaction.

Operations for processing a check payment during a sales transactionutilizing the present invention are illustrated in FIG. 4. The checkprovided by the customer is inserted into the printer in insertionregion 202, aligned on alignment edge 206 and placed face down at block300. The check is moved past optical reader 10 to read the MICRinformation at block 302. It may also be moved past a magnetic reader toread the same MICR information magnetically (block 304).

During read block 302, the check may be held in the focusing axis 22 ofthe optical reader 10 by the structures defining document travel path104 or other means for positioning the document adjacent optical reader10. Both the magnetically and optically read coded information is thenpassed along to a terminal or other controller at block 306. Characterrecognition of the MICR information may be performed in real time by acontroller. If this controller is located in the printer, theinformation read by optical reader 10 may be transmitted by the printerof the present invention in the form of alphanumeric charactersrepresenting information such as the account number the check is to bedrawn against. Real time character recognition also provides for errordetection to initiate rereads.

The check is then cleared, either by remote access to the bank computerto confirm a sufficient balance and debiting the account for the amountof the transaction or by checking the account number against a database, for example of known bad checks, maintained at the store usingtechniques known to those of ordinary skill in the art. After the checkis cleared, print data, typically endorsement information, is receivedby the printer at block 308. The check is then moved along documenttravel path 104 and print head 200 prints the endorsement information onthe back of the check at block 310. The check is then removed from thepoint of sale printer device 100. Alternatively, the point of saleprinter device 100 of the present invention may also be used to printother known information on the front of the check such as payee, dateand amount so that the customer need only provide a signature on thecheck.

While the invention has been described with specificity above withreference to the dot matrix printer and optical reader illustrated inthe drawings, it is to be understood that the present invention islikewise directed to other types of printers and to other methodspresently used or which may in the future be used for encodinginformation on transaction documents such as checks.

Operations related to use of both a magnetic and an optical reader willnow be further described according to an embodiment of the presentinvention. As described above, a check is inserted into the point ofsale printer device 100 and awaits a command from a terminal to startthe MICR reading process. Once this command is received, the check isfed past a magnet that magnetizes the magnetic ink particles embedded inthe MICR characters. This provides a magnetic field that the magneticread head should be able to detect. The check then traverses past theoptical reader 10 where slice data is recorded for each character. Thisdata is stored, for example, in a Random Access Memory (RAM) and may beoperated upon after the read process is completed. A magnetic read headfollows and produces an analog signal representing the wave forms foreach character. This signal is sent to an input of an A/D converter(analog to digital) which provides a digital representation of theanalog MICR signal. Like the optical data, the digital data from themagnetic read head is stored in RAM for further processing.

The primary decode is preferably from the magnetic sensing data. If themagnetic decoding process cannot properly decode one or more characters,then an optical decode is enabled using the data from optical reader 10.The optical decoding can be used to identify those MICR characters thatcould not be identified based on the magnetic decoding. If the opticaldecoding removes all the read errors from the MICR character set of thecheck, the data may then be passed to the terminal for furtherprocessing. If errors still exist, the process may be repeated one ormore times until all of the MICR characters are read successfully. Ifthe subsequent pass(es) still produce errors in reading some of the MICRcharacters, an error message may be sent to the terminal.

If a successful read is obtained by the magnetic reader, opticaldecoding may still be invoked to be used as part of a “Scoring” processfor determining the confidence level of character prediction. This mayresult in a higher degree of accuracy in the prediction process andfewer substitution errors (misidentifying a character). The opticaldecoding may, therefore, be used in a variety of ways including: 1)verify the characters read magnetically; 2) provide backup data forthose characters that could not be read magnetically; 3) provide anentire character set worth of data in a high magnetic/electric noisefield environment, and; 4) factored in the “Scoring” process whendecoding a character.

In the drawings and specification, there have been disclosed typicalpreferred embodiments of the invention and, although specific terms areemployed, they are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being set forthin the following claims.

That which is claimed:
 1. An optical reader comprising: a base member;an optical sensor array connected to said base member; a housingpositioned over the optical sensor array and defining a chamber in whichthe optical sensor array is positioned; a light source positioned in thechamber defined by the housing; wherein the housing includes areflecting surface portion positioned to receive light from the lightsource and direct the received light through the chamber towards afocusing axis at a first end of the housing; and wherein the reflectingsurface portion of the housing includes an optically transmissive innerlayer and a reflective cladding outer layer on a surface of theoptically transmissive layer opposite the chamber.
 2. An optical readeraccording to claim 1 wherein the housing is connected to the base memberto provide an enclosure protecting the optical sensor array and thelight source from debris.
 3. An optical reader according to claim 2wherein the housing is connected to the base member so as to positionthe focusing axis in alignment with the optical sensor array.
 4. Anoptical reader according to claim 3 wherein the housing includes a firstportion extending up from the base member and wherein the reflectingsurface portion extends from an end of the first portion opposite thebase member towards the focusing axis at an angle selected to receivelight from the light source and direct the received light through thechamber towards the focusing axis.
 5. An optical reader according toclaim 1 wherein the housing is connected to the base member so as toposition the focusing axis in alignment with the optical sensor array.6. An optical reader according to claim 1 wherein the housing includes afirst portion extending up from the base member and wherein thereflecting surface portion extends from an end of the first portionopposite the base member towards the focusing axis at an angle selectedto receive light from the light source and direct the received lightthrough the chamber towards the focusing axis.
 7. An optical readeraccording to claim 1 wherein the base member is a circuit board andwherein the light source and the optical sensor array are electricallyconnected to the circuit board and wherein the optical sensor is mountedon the circuit board.
 8. A point of sale device comprising: a housing; adocument driver mounted in the housing to move a document inserted intothe point of sale device along a document travel path; a magnetic readermounted in the housing and positioned along the document travel path toread MICR coded information from the document; an optical reader mountedin the housing and positioned along the document travel path to read theMICR coded information from the document; wherein the optical readercomprises: a base member; an optical sensor array connected to said basemember; a sensor housing positioned over the optical sensor array anddefining a chamber in which the optical sensor array is positioned; alight source positioned in the chamber defined by the sensor housing;wherein the sensor housing includes a reflecting surface portionpositioned to receive light from the light source and direct thereceived light through the chamber towards a focusing axis at a firstend of the sensor housing; and wherein the optical reader is mounted toposition the focusing axis so that a portion of the document containingthe MICR coded information passes through the focusing axis when thedocument is moved along the document travel path.
 9. A point of saledevice according to claim 8 wherein the sensor housing is connected tothe base member to provide an enclosure protecting the optical sensorarray and the light source from debris.
 10. A point of sale deviceaccording to claim 8 wherein the sensor housing is connected to the basemember so as to position the focusing axis in alignment with the opticalsensor array.
 11. A point of sale device according to claim 8 whereinthe sensor housing includes a first portion extending up from the basemember and wherein the reflecting surface portion extends from an end ofthe first portion opposite the base member towards the focusing axis atan angle selected to receive light from the light source and direct thereceived light through the chamber towards the focusing axis.